The double burden of obesity and iron deficiency on children and adolescents in Greece: the Healthy Growth Study.

BACKGROUND: Some small cohort studies have noted that obesity co-exists with lower serum iron levels. The present study aimed to examine the association between being overweight and iron deficiency (ID) in a large cohort of Greek children and adolescents. METHODS: A representative sample of 2492 primary schoolchildren aged 9-13 years old was examined. Anthropometric, biochemical, clinical, dietary intake and physical activity data were collected. RESULTS: The prevalence of ID and iron deficiency anaemia (IDA) was higher in obese boys and girls compared to their normal-weight peers (P < 0.05). Serum ferritin was higher in obese compared to normal-weight boys (P = 0.024) and higher in obese compared to normal-weight and overweight girls (P = 0.001). By contrast, a negative association was found between transferrin saturation and adiposity in both boys and girls (P = 0.001 and P = 0.005). Furthermore, obese girls had significantly higher fibre intake than normal-weight girls (P = 0.048) and also overweight and obese boys and girls recorded significantly fewer pedometer steps than their normal-weight peers (P < 0.001). Finally, obesity more than doubled the likelihood of ID in both boys (odds ratio = 2.83; 95% confidence inteval = 1.65-4.85) and girls (odds ratio = 2.03; 95% confidence interval = 1.08-3.81) after controlling for certain lifestyle and clinical indices as potential confounders. CONCLUSIONS: The present study shows that obese children and adolescents were at greater risk for ID and IDA than their normal-weight peers. Low grade inflammation induced by excessive adiposity may be a reason for the observed low iron levels. This is also strengthened by the elevated serum ferritin levels, comprising an acute phase protein that is plausibly increased in inflammation.

Dairy intake associates with the IGF rs680 polymorphism to height variation in periadolescent children.

BACKGROUND/OBJECTIVES: Height is a classic polygenic trait, with a number of genes underlying its variation. We evaluated the prospect of gene-to-diet interactions in a children's cohort, for the insulin-like growth factor II (IGF) rs680 polymorphism and height variation. SUBJECTS/METHODS: We screened 795 periadolescent children (424 girls) aged 10-11 years old from the Gene and Diet Attica Investigation (GENDAI) pediatric cohort for the IGF rs680 polymorphism (rs680). RESULTS: Children homozygous for the common allele (GG) were taller (148.9+/-7.9 cm) compared with those with the A allele (148.1+/-7.9 cm), after adjusting for age, sex and dairy intake (beta+/-s.e.: 2.1+/-0.95, P=0.026). A trend for rs680 x dairy intake interaction was also revealed (P=0.09). Stratification by IGF rs680 genotype revealed positive significant (P=0.014) association between dairy product intake and height in A-allele children adjusted for the same confounders. A daily increase of four dairy servings was associated with a 0.4 cm increase in height. On grouping dairy intake into low (1.9+/-0.7 servings per day) and high dairy product consumption (4.4+/-1.5 servings per day), children with the A allele who were high dairy product consumers were taller compared with the low dairy product consumers (148.8+/-7.9 vs 147.4+/-7.7 cm, respectively, P=0.05). CONCLUSIONS: A higher consumption of dairy products is associated with increased height depending on the rs680 IGF2 genotype.

Changes in free radical generation and antioxidant capacity during ultramarathon foot race.

BACKGROUND: Exhaustive exercise has been implicated in the generation of reactive oxygen species, resulting in oxidative stress. We studied the effect of a long-distance, endurance exercise on oxidative stress parameters in athletes who participated in the ultramarathon race Spartathlon (246 km). MATERIALS AND METHODS: This study included 18 runners (16 men and 2 women) aged 42.8 +/- 1.4 years. Blood samples were obtained 24 h before (prerace), at the end (postrace) and 48 h after the end of the race (48 h postrace). We measured oxidative stress indices, including red cell glutathione, malonyldialdehyde and 8-iso-prostaglandin F(2a), as well as the total antioxidant capacity. RESULTS: 8-Iso-prostaglandin F(2a) level increased significantly at the end of the race, compared to prerace levels (up to 914.7 +/- 61.4 pg mL(-1) from 197.6 +/- 8.4 pg mL(-1)), and remained 2.5-fold increased over the baseline 48 h after the race (532.0 +/- 54.2 pg mL(-1), P < 0.000). The total antioxidant capacity of the athletes increased from a baseline of 289.6 +/- 9.0 micromol L(-1) to 358.7 +/- 11.0 micromol L(-1) immediately after the race and remained elevated 48 h later (350.6 +/- 7.6 micromol L(-1)) (P < 0.001). CONCLUSIONS: Prolonged exercise induces a marked response of oxidative stress biomarkers, which in part is compensated by serum ability to scavenge free radicals. Whether these changes have long-term negative effects in the organism needs further investigation.